The invention relates to a method for treating waste materials containing halogen, especially, bromide, permitting the recycling of useful materials while generating energy.
Electrical and electronic waste materials contain a number of toxic compounds. Among these toxic compounds are mainly halogenated hydrocarbons, especially brominated hydrocarbons. Brominated hydrocarbons are often used in fire protection mediums. The bromine content may be 20 to 40 wt %. In many cases, tetrabromine biphenol A is used in fire-retarding agents. Other often used bromine-containing compounds are polybrominated diphenyl ether and B is (Tribromine phenoxy)ethane. But also chlorine containing hydrocarbons and hydrocarbons which contain chlorines as well as bromine, are important.
A common method for treating waste materials containing toxic compounds is to subject them to a pyrolysis process. Compared with other decontamination processes such as combustion or deposition, pyrolisis has the advantage that chemical compounds and energy can be recuperated. However, in connection with waste material containing halogens and particularly bromine and chlorine, this method is problematic since a wide spectrum of additional compounds is generated. For example, tetrabrominebiphenol A forms toxic mono- and di-bromine phenols. Other typical pyrolysis products are halogenated p-debenzodioxines (PBDD) and p-dibenzofuranes (PBDF). The advantage of energy generation and material recuperation is therefore counterbalanced by the toxicity of the pyrolysis products.
DE 44 25 658 C1 discloses that the polyhalogenated compounds can be removed from the exhaust gas of a combustion plant by contact with polyolefins, particularly polyethylene and polypropylene. However, in that case, the polyhalogenated compounds are adsorbed in the polyolefins only reversibly so that they can again be desorbed under suitable conditions. For a long-term immobilization of these halogenated toxic compounds polyolefins are not suitable as adsorption materials under the limit conditions as described in the cited patent.
It is the object of the present invention to provide a method for the treatment of waste materials containing halogenated, particular bromine-containing compounds, wherein valuable compounds and/or energy can be recuperated as it is generally possible with pyrolysis methods and the waste materials are destroyed at least to a large extent, whereby essentially no additional halogenated hazardous materials are generated.